Despite constant change, a healthy city remains accessible and financially affordable, with neighbourhoods in which different social milieus live together side by side.
Changes in the cityscape must not lead to the expulsion of the "traditional". Instead they should conscientiously combine cultural heritage with newer influences. This enables identification with one's own district to be maintained and promoted.
Identification with one's own neighbourhood is a community-building factor that promotes the social cohesion and sense of belonging of old and new residents.

Economic action is the main driver of urban development. Private and public investments create space for working, living, everyday life, leisure and consumption. The second half of the 20th century in Europe was characterised by the principles of the social market economy and the welfare state, through which space was to be made available to all milieus in a socially acceptable way. Since the 1980s, state production of urban infrastructure and residential and commercial space has been increasingly criticised and transferred to private developers and owners. In addition, over the past ten years, the acquisition and trading of urban land and real estate has established itself as a profitable investment model and led to the development of corresponding financial market products.

The result is a comprehensive financialisation of housing in European metropolises. Financialisation should be understood as a shift in power from the real economy to the financial sector. However, the resulting appreciation of real estate in anticipation of profit leads to the displacement of certain income groups in certain neighbourhoods. The resulting gentrification is now analysed in critical urban research as a global mode of economic accumulation.

Increasing housing shortages accompanied by worries about loss of housing or relocation increase existential fears and thus have a negative impact on the mental health of city dwellers.

Gentrification also entails the segregation of urban milieus, in particular the expulsion of lower income groups from the city centre and urban areas close to it – which is well advanced in many German cities. Such social segregation in cities leads to changes in the sense of belonging to a social group.

Numerous studies assess gentrification and segregation as a threat to social cohesion from a sociological and human-geographical point of view. It is assumed that increasing housing shortages, fear of homelessness or relocation, and the social segregation of cities have an influence on the mental health of the population. This process of displacement or more difficult participation in central urban services has an impact on the resilience of city dwellers. Under the impact of current urban transformations, the relationship between income and the costs of housing and living therefore play an increasingly important role for mental health.

If apartment owners and tenants feel less responsible for their property or their district, this reduces the experienced self-efficacy and the personal will to participate in urban events.